
\documentclass[a4paper, 12pt]{article}
%\usepackage[utf8]{input enc} % this will save the document as utf8
%\usepackage[T1]{font enc}   % this handles font encoding

\begin{document}


This is my document. I just want to learn how to use \LaTeX .

\section{white space and list}

\noindent There is no indent in this paragraph.  The length~$1$ of the rod. The lenght $1$ of the rod. There are some good news etc. Mr.\ Smith. 

\begin{enumerate}
\item The first item.
\item The second item.
\item The third item.
\end{enumerate}

\begin{itemize}
\item The first item.
\item The second item.
\item The third item.
\end{itemize}

\begin{description}
\item The first item.
\item The second item.
\item The third item.
\end{description}

\section{other}

\begin{verbatim}

for(int i=0; i<10; i++){
}

$math will not be math either$
\end{verbatim}


\begin{tabular}{ccc}
1 & 2 & 3 \\
abc & def & ghi
\end{tabular}

\section{math}

This is inline math mode using \$ \$ or \textbackslash(\textbackslash ) $f(y)=x^2$

This is own line math mode by [] or \textbackslash begin\{equation\} \textbackslash end\{equation\}, which will numbering the equation like the second one. 

\[ f(x)=x_1^2+x^2_2+...+x^2_n \]

\begin{equation}
E=mc^2
\end{equation}

Greak letters: $ \alpha, \beta, \gamma, \delta$...


 $\Gamma, \Delta...$

One can also change font in math: for example $\mathbf{u}$ and $\mathbf{v}$ are vectors. 

\[ V=(\mathbf{u} \times \mathbf{v} ) \cdot \mathbf{w} \]

Caligraphic font are only available in capital letters. 

\[\mathcal ABCDEFG\]

Functions can be used directly

\[ cos(\theta + \phi ) \inf(a) \] 
\[ \cos(\theta + \phi) \]

Embeded text in math

\[ M=\{ f \in V' : f(m)=0 \} \mbox{ for all } m \in M \]

Fraction and roots:

\[ \frac{x}{y}  \sqrt[n]{b^2 \pm 4ac}\]

Elipse is different from three dots $x...y$, $x \ldots y$, $x \cdots y$

Accents: $\underline{a}, \overline{a}, \hat{a}, \tilde{a}$.

Delimiters: $\|f\|$, $\left( f \right) \left\{ f \right\} $

If I have learnt it. I can use it to write articles. 

\emph{emphasize this text here}

Let $D$ be a subset    of $\bf R$.

d  and $\delta$ are different

in line math are like this \$ math \$   =  $math$.

\[ stand alone math |x^2+y^2=z^2\] 

left quote`  and right quote '  never use double quote 

double quote can be like this ```which is not necessary '\,''

\section{\LaTeX article structure}

\subsection{this is 2nd headings}
 
\subsubsection{this is 3rd headings}

\paragraph{can there be pargraph}
content of this paragraph

\subparagraph{subparagraph}
content of sub paragraph

\subsection{this is 5th headings}


\section{font}
This line shows \emph{emphasize} and \textbf{boldface}.

{\bf Boldface} {\it italic} {\sf what's sf?sans serif} {\tt what's tt} {\sl sl should mean slanted same as italic} {\rm rm should be roman, which is normal font}

\tiny This is tiny font

\scriptsize This is script size

\footnotesize This is footnote size

\small This is small size

\normalsize This is normal size

\large This is large size

\Large This is even larger

\LARGE This is LARGE

\huge This is huge

\normalsize

Is this normal text

\textup \\textup is normal text

Can \LaTeX handle öäå?

\end{document}
